Now that this topic has anyway been bumped, I can ask a couple of questions with less guilt.
It looks like power to the rear differential is going directly instead of going through the middle differential. Why is it done this way ? Is it to support independent suspension between the two sets of wheels ?
Also, what exactly is the purpose of these parts:
I have not seen the parts in real life, so was unable to get a feel for them.

Glad to see Technic invading into other themes as TLG tries to make things more functional.
This modular set has the Technic suspension arm being used as a tow arm for a city scale truck. Also uses this Technic piece which has ironically not appeared in Technic sets so far.

This is so cool !
It looks simple enough at first glance, but when I look carefully, I can see so many small details which add up to make the whole thing work.
I really admire the skills needed to make these working Technic contraptions.